using ImageGear.Core;
using ImageGear.Formats;

// JPG Compression.
public ImGearFileFilters SetJPGCompressionParameters(ImGearJpegSaveType jpegSaveType, int chrominance, int luminance)
{
           // Create local control parameters for the filter corresponding to the format to be compressed (i.e. the global filter is not modified).
           ImGearFileFilters localFilters = new ImGearFileFilters();

           // Replace native ImageGear JPG filter with extended filter.
           localFilters.Set(ImGearCommonFormats.CreateJpegFormat());

           // Get control parameters for the target format.
           ImGearFormatParameters formatParameters = localFilters.Get(ImGearFormats.JPG).Parameters;

           // Set the parameters related with the compression intended.

           // Set output type for JPG format.
           // Possible values: ImGearJpegSaveType.Lossy; ImGearJpegSaveType.Lossless; ImGearJpegSaveType.Progressive.
           formatParameters.GetByName("SaveType").Value = (int)(jpegSaveType);

           // Set image color quality for Lossy compression ([0, 255]).
           formatParameters.GetByName("Chrominance").Value = chrominance;

           // Set luminance (grayscale) quality for Lossy compression ([0, 255]).
           formatParameters.GetByName("Luminance").Value = luminance;

           return localFilters;
}

// Set common image save options for conversion.
public ImGearSaveOptions SetConversionParameters()
{
           ImGearSaveOptions saveOptions = new ImGearSaveOptions();
           
           // Set conversion mode.
           // Allow any conversion supported by ImageGear: ImGearRasterConversionModes.ANY.
           // See ImGearRasterConversionModes enumerator for more options.
           saveOptions.ConversionMode = ImGearRasterConversionModes.ANY;

           // Set target color space.
           // Preserve source color space: ImGearColorSpaceIDs.NONE.
           // See ImGearColorSpaceIDs enumerator for more options.
           saveOptions.ForceColorspace = ImGearColorSpaceIDs.NONE;

           // (Optional). Use only if we want to conduct compression.
           // Set the filters for JPG Lossy compression.
           // Chrominance = 30 and Luminance = 24 provides about a 12:1 image compression ration with minimal data loss.
           saveOptions.Filters = SetJPGCompressionParameters(ImGearJpegSaveType.Lossy, 30, 24);

           return saveOptions;
}

// Save PNG image converted and compressed to JPG format based on the options available in ImageGear .NET.
public void SavePNGToJPG(ImGearPage loadedPNGPage, string outputJPGFilePath)
{
         // Specify options for saving.
         ImGearSaveOptions saveJPGOptions = SetConversionParameters();
         ImGearSavingFormats destinationFormat = ImGearSavingFormats.JPG;

         // Save to JPG file.
         using (FileStream fileStream = new FileStream(outputJPGFilePath, FileMode.OpenOrCreate, FileAccess.ReadWrite))
         {
                ImGearFileFormats.SavePage(loadedPNGPage, fileStream, 0, ImGearSavingModes.OVERWRITE, ImGearSavingFormats.JPG);
         }
}